1. Field of the Invention
This invention relates to systems for the control of fluid flow control valves which are used to control the supply of fluid to an actuator for the control of the movement of a component. There are many applications for such control systems. For example, the control of a tractor implement hitch, the control of a combine harvester table, the control of a tractor front loader and the control of a tractor backhoe.
2. Description of the Prior Art
Typically the valves used in such control systems include a valve member such as a spool whose position is controlled either directly or indirectly by one or more solenoids in order to adjust the flow of fluid through the valve and hence the movement of the component.
In order to provide an accurate and efficient control function with such a valve much time and attention has been given to the design and development of valves whose through flow rate is predictably proportional to the applied signal. Experience has shown that the provision of such valves is expensive.